VGen <- function(m, a, b)
{
     V = matrix(0, m, 1)
     coin = sample(0:1, m, replace = T, prob = c(0.5,0.5))

     for(i in 1:m) {           
           if(coin[i] == 0) 
           {
                 V[i,1] = 0
           } else
           {
                 V[i,1] = runif(1, a, b)
           }
     }
     
     return (V) 
}